Calculate Q Liters of bloodmin given the following VO2 04 L

Calculate Q (Liters of blood/min) given the following: VO_2 = 0.4 L of O_2/min, CaO_2 = 20 ml of O_2/100 ml blood and CvO_2 = 14 ml of O_2/100 ml of blood a) Calculate SV (ml/beat) given a heart rate of 85 beats/min. b) Is this person closer to rest or strenuous exercise? Provide all the evidence to support your answer. C) Show all your work including units. Calculate a normal (typical) resting Mean Arterial Pressure. What (and how much) is the response of Systolic and Diastolic BP to exercise? What (an how much) affect would doubling the radius of the blood vessel have on blood flow? Show any equations and/or calculations. Fill in the following flow chart regarding the Frank-Starting mechanism.

Solution

1.

a)

Stroke volume = end diastolic volume – end systolic volume

Cardiac output = heart rate * stroke volume

CO = VO2 / (Ca - Cv)

= 400 / (20-14)

= 400/6 = 66.667mL/min

Stroke volume = cardiac output / Heart rate

SV = 66.667/85 = 0.784 mL/beat

b)

The resting stroke volume of an average person is 70ml/beat. Here, the stroke volume is 0.784 mL/beat

Decreased venous return causes reduction in stroke volume. Other factors that reduce the stroke volume are reduced vascular resistance, sodium and potassium concentrations, hypothermia, hypoxia, calcium channel blockers, and parasympathetic stimulation.

Preload increases stroke volume by causing increase in the venous blood flow.

Therefore, venous return reduction could have caused reduced stroke volume

2.

Mean arterial pressure is determined by cardiac output, systemic vascular resistance and central venous pressure. Alterations in cardiac output or systemic vascular resistance affect mean arterial pressure.

During strenuous exercise, systolic blood pressure increases very high while diastolic blood pressure do not rise much.

3.

The flow of blood increases with increase in radius of the blood vessel.

4.

Skeletal pump, smooth muscle within walls of veins, respiratory pump and gravity are the factors that enhance the venous return.

Myocyte stretching enhances the force that makes the heart to release venous return.

Increased venous return enhances the ventricular filling and the preload occurs.

Increase in blood volume that return to the heart increases stroke volume and cardiac output.